Every Sunday Morning When Marco Was a Young Child,his Family

Multiple Choice

Every Sunday morning when Marco was a young child,his family would have a special breakfast complete with freshly baked cinnamon rolls.To this day he finds himself smiling whenever he smells cinnamon rolls baking.In this example,what is the smell of cinnamon rolls

A)  cue
B)  conditioned stimulus 
C)  unconditioned stimulus
D)  discriminative stimulus